1. Field of the Invention
The present invention relates to a carrier for an electronic component, and to use of the carrier to mount an electrical component having one or more connection pins to a circuit board.
2. Related Art
During manufacture of an electrical assembly comprising a circuit board with one or more electronic sub-assemblies mounted on the circuit board, it is often necessary for electrical connections from the sub-assemblies to be inserted into through-plated holes or connector sockets on the board. To improve assembly efficiency, it is common practice to provide a funnel shaped entry or “lead in” to the sockets. This allows for a certain amount of error in the component alignment during assembly. This solution is effective in many cases, but may not always be sufficient to meet assembly requirements.
A particular problem arises in the production of automotive display units. These units often include a multitude of components such as a speedometer, engine condition gauges, warning lights and information displays. Warning light and display components may be held by a moulded carrier affixed to a circuit board. Back-lighting may then be provided behind the carrier to illuminate a display or symbols printed on the carrier. With such display units, a liquid crystal display or light emitting diode may be offset from the circuit board by a distance, for example by mountings on the carrier. Electrical connection pins then need to span to offset between the electronic components and the circuit board. It is then often necessary to insert long flexible connection pins into through-plated holes or a socket in the board.
It is difficult to automate such an assembly process because of the fragile nature of the pins, and the close tolerances needed to correctly insert a pin into a matching hole or socket, particularly when there are short production times. Manual assembly is relatively expensive and prone to errors. A pin may be bent or mis-inserted, leading to a faulty electronic assembly. Damaged sub-assemblies including a number of electrical components may be relatively expensive to re-work or to discard, leading to a certain wastage of components when parts become bent or broken during assembly.
If electrical connection pins are particularly long or flexible, it may be impractical to insert these into a matching socket, because of the tight fit required to make a good electrical connection. Long pins may be prone to bend upon insertion into a socket. Therefore, in some cases it is not possible to use a connecting socket, and the connection has to be made by soldering pins to the circuit board. It is generally desirable to use single-sided circuit boards, and surface-mounting techniques, to reduce cost. However, moulded carriers and sensitive electronic elements such as liquid crystal displays can be damaged by heat from soldering, which necessitates that soldered connections are made on the side of the circuit board opposite the carrier or component. Since electrical connections may be required on the side of the board towards the carrier or display, for example for a surface mounted speedometer unit, this means that a double-sided board has to be used, thereby increasing cost.